I'll probably be accused by some random ex-route-Herc fella of not telling the truth (again), but our basic rotary course on Whirlwinds at Shawbury learned the true value of alert crewmen when one of the 2 MACR crewman instructors happened to look up during an early LL Nav trip being flown by one of the fellas 2 courses ahead of me. This crewman instinctively reached out and grabbed the 1/4 mill chart flying at 80-odd knots that had just made its way out of the open cockpit window then calmly passed it back up between the pilot's legs, mere seconds after the stude started to think he'd failed the trip. ISTR the pilot, who shared his surname with that of a town in the N Midlands, went on to enjoy a career on Bucc's after one token SH tour - no problems with open windows on those, I believe.